Ideas

Whatever I feel like talking about.

Saturday, June 30, 2007

Why No Built-in Paternity Testing?

My previous attempt to use this blog as a tool for open source assistance in my current writing project was a great success; I have incorporated results from the query in my previous post into the draft of Future Imperfect. So I decided to try again.

Pair mated species, such as humans and many birds, follow a mating pattern of monogamy tempered by adultery. The female pairs with the best male who will pair with her then, given the opportunity, gets pregnant by the (genetically) best male available. Males spend time and effort attempting to engage in extra-pair copulations while preventing their mates from doing so.

A simple solution to the problem faced by males, and one now provided by modern technology, is paternity testing. If a male can tell which of his mate's children he fathered he can decline to help support the others, giving his mate a strong incentive not to cheat on him. My question is why that solution was not long ago implemented by Darwinian evolution. Why do males in such species not have some way of identifying their offspring?

One possible answer is that here, as elsewhere in evolutionary biology, we have an arms race. It is in the interest of males for them to be able to identify children born by their mates to other males but in the interest of females for them not to be able to do so; more precisely, it is in the interest of the female to be able to fool the male into thinking that another male's children are his. It is not clear to me why the females could be expected to win this particular conflict, but perhaps there are reasons that have not occurred to me.

Wednesday, June 27, 2007

Wanted: Stories on Open Source Crime Control

Over the years, I've come across a number of news stories describing successful efforts by victims, typically of fraud, to use the internet to contact each other, identify the guilty party, and bring him to the attention of law enforcement. I seem to have saved only one such story, however, and would like more for a discussion I'm putting in Future Imperfect. Can anyone offer examples and links?

Tuesday, June 26, 2007

Global Warming, Depletable Resources, Inconsistent Beliefs

A recent post on FuturePundit cites some interesting calculations by CalTech professor Dave Rutledge. Using the estimation approach on which current, widespread concerns about running out of petroleum are based, he finds that the IPCC global warming calculations overestimate future hydrocarbon burning by a factor of at least three or four--because the hydrocarbons are not there to be burned.

We have here two different arguments leading to the same conclusion and believed, on the whole, by the same people. One argument is that we are running out of hydrocarbons and should therefore reduce our use of hydrocarbons, reduce energy consumption and switch to alternative energy sources. The other argument is that we are, by burning hydrocarbons, increasing the amount of CO2 in the air and warming the planet, and we should therefore reduce our use of hydrocarbons, reduce energy consumption, and switch to alternative energy sources.

Both arguments claim, with some justification, to be based on scientific calculations. Both are, on the whole, believed by the same people. But, if Rutledge is right, the two sets of calculations are inconsistent with each other. Nobody who believes one ought to believe the other.

Which may reflect the fact that, once you know what conclusion you want to reach, there is always some way of getting there.

Monday, June 25, 2007

Blocking Spam: An Idea

Consider a firm filtering out spam for a million customers. One way of identifying spam is to look for messages received by multiple customers. If ten thousand people receive identical messages, it is a pretty safe bet that they are all spam.

One problem with doing this is privacy; the customers do not want someone else to be reading their mail. The comparison would, of course, be done by computer, but once the message has been sent to the spam filtering company, the customer has no way of knowing who, other than a computer, is looking at it.

There is a simple solution to the problem. Instead of forwarding your email to the filtering company, forward a hash of your email. Your own computer applies a one way hash function to each message, calculating from it a long number. If the number is long enough, the probability that two different messages will hash to the same number becomes vanishingly small. But a twenty digit number still contains much less information than a hundred word email, so there is no way of reversing the process and deducing the message from its hash. Forward the hash to the spam filtering company--doing that not only protects your privacy, it also takes a lot less bandwidth than forwarding the email. Get back information on whether or not it matches the hash of messages received by many other customers, and junk or read the email accordingly.

Have I just reinvented the wheel? Is anyone currently using some variant of this approach?

Sunday, June 24, 2007

Love Drugs and the Future of Marriage

There is considerable evidence that both falling in love and long term attachment are associated with the levels of various chemicals in the brain. Suppose we learn enough about the process to be able to control it artificially. What might the results be and should we approve?

A couple fall in love and get married. To properly regulate their emotions thereafter, they get a prescription for a few months of "being in love" drugs and use them to enjoy their honeymoon and the beginning of their marriage. Being in love is too intense an emotion for the long term, so they then switch to the "long term attachment" prescription. Later, as their schedules permit, they temporarily switch back in order to experience a second, third, fourth honeymoon.

That is, however, only the first step in the social changes made possible by the new technology. Currently, falling in love is usually a necessary step in the process that leads to marriage. But should it be? It is not at all obvious that the person you fall in love with is the best candidate for a long term relationship—a point made long ago by defenders of the old system of having parents choose mates for their children. Our emotions, after all, are driven by processes generated by Darwinian selection in a very different environment and "designed" not for our happiness but for reproductive success—the interest not of us but of our genes.

The new drugs provide a new option—choice of mate not by either our parents or our hormones but by our reason. You employ some suitable search strategy to find a woman who is well suited to be your wife and will think you well suited to be her husband. Once the marriage contract is signed, the final step in the ceremony is for both of you to take your love drugs. You look deep into her eyes ... .

Subjectively Right, Objectively Wrong: A Moral Question

What are the moral implications of an act that is subjectively justified—within the actor's rights given what he reasonably believes the facts to be—but objectively wrong?

Suppose, for example, I correctly believe someone is trying to kill me. You, a stranger, take some entirely innocent act which I reasonably interpret as the beginning of an assassination attempt. I attack you, injure you, and then discover my mistake. What ought to happen to me?

The answer that fits my intuition—I think I could justify it in terms of the economic analysis of law, but that isn't the approach I'm interested in at the moment—is that I am guilty of a tort but not a crime. I have injured you and so owe compensation but did not intend to violate your rights and so do not deserve punishment.

Now, to make the question more interesting, replace me by the government. You are arrested for a murder you did not commit, convicted on convincing evidence, and jailed awaiting execution. The only way in which you can save your life is by escaping, killing a guard in the process; you do so. A month later—after you would have been executed if you had not escaped—someone else confesses to the murder, providing absolutely convincing evidence of your innocence. What now is your status? Are you a murderer because you killed a guard? Or are you innocent on grounds of self defense, with perhaps a claim against the government for false imprisonment?

The government and the guard were subjectively innocent, since they reasonably believed you were a murderer and so deserved to be executed (I'm not interested, at the moment, in whether capital punishment itself is morally justified—it just makes the example simpler). But they were objectively guilty, since in fact you were not a murderer and they were thus attempting to kill you when you did not deserved to be killed. You are both subjectively and objectively innocent of killing someone without justification, since they were in fact trying to kill you and you had no other way of defending yourself—unless their subjective innocence makes their actions morally correct.

Do other people agree with my intuition—that you are innocent, the government and its agents liable to you for damages but not deserving of punishment? If not, do you have a different approach to such situations, preferably one that applies to both private and state actors?

Tuesday, June 19, 2007

Cells Need to Talk to Each Other

It seems clear that both aging and cancer are at least in part due to the accumulation of mutations in individual cells. Seen in the abstract, in terms of information, this is surprising. Our genetic information, after all, is massively redundant; mutations aside and ignoring a few special cases, every cell contains a copy of the same genotype. All a cell has to do in order to identify a particular sequence as a mutation is to check with two or three of its neighbors and see if they have it.

This suggests a possible strategy for life extension. Once our technology is good enough—not, unfortunately, any time soon—create some mechanism to exploit the redundancy, some way of identifying mutations by majority vote and eliminating them.

Wanted: The Hedonist's Life Extension Diet

I've been reading through the archives of the FuturePundit blog, accumulating ideas and links for my Future Imperfect. One of things I notice is that, of the things there is some evidence are good for you, a considerable number are also good. That includes pistachios (mentioned in a previous post), chocolate, pomegranate juice, green tea, wine (for those that like wine), and probably lots of other things.

There is clearly an opportunity here for an ambitious author. Write a book on how to live longer and enjoy it more, putting together everything known about such foods. And if the book sells, there are further market opportunities. Chocolate covered pistachios, say, using whatever sort of chocolate is highest in the relevant chemicals. Green tea flavored with pomegranate juice.

In an old Playboy interview, H.L. Hunt responded to an interviewer who assumed that he subsidized his (right wing) radio stations by assuring him that they made money. "If this country is worth saving, it's worth saving at a profit."

"If your life is worth extending, it's worth taking pleasure in extending it" isn't quite as good a line; perhaps someone can come up with a better version.

Sunday, June 17, 2007

Advice People Will Take

Future Pundit has a recent post about research suggesting that pistachios are good for your heart. The final sentence in the bit he quoted:

"What's more, we noted very good compliance and a positive response from participants during the four-week period."

I was struck long ago, reading the literature on whether large doses of vitamin E were or were not good for you, with the prejudice among some medical writers against anything that's easy to do--"popping pills" instead of regular exercise, for instance. As this example suggests, they have it backwards. If you find things good for people that they actually like doing, they are much more likely to do them. Even I could be persuaded to eat pistachios on a regular basis—for the good of my heart, of course.

Saturday, June 16, 2007

Sex, Pleasure, Circumcision and Economics

Ronald Bailey has a post on Sexual Pleasure vs. Sexual Health: The Circumcision Trade-Off. The argument is that circumcision reduces the risk of getting AIDS but also reduces sensitivity and so pleasure.

I have no idea how good the evidence is, but it strikes me that there is a serious logical problem with one step in the argument—from less sensitivity to less pleasure. The limiting factor to duration of sexual intercourse, under most circumstances, is male endurance; one can plausibly model the process as a rising intensity of pleasure up to the point of orgasm, with total utility equal to the area under the curve. If so, greater sensitivity simply means that you reach the same maximum sooner, reducing the area under the pleasure curve.

And that's without even considering the utility of the other participant in the process.

Wednesday, June 13, 2007

The Diversity Scam

“Diversity,” in the academic context, is usually a euphemism for affirmative action, itself a euphemism for discrimination--variously racial, ethnic, gender or sexual preference based--in favor of groups viewed as disadvantaged. In the employment context, a diversity hire is someone hired in part because he is black, or she is female, or …. .

What I find particularly irritating about this usage is that those who adopt it are typically opponents of actual diversity. In the academic context, what matter are ideas. Two professors with different gender or skin color but the same views provide less relevant diversity than two professors of the same gender or skin color but sharply opposed views.

Supporters of “diversity” try to obscure this by arguing that a different racial or gender background leads to a different viewpoint. There may be cases where this is true, although it is hard to see its relevance to most academic fields. But in such cases, favoring prospective hires whose work shows a different and original viewpoint is surely more sensible than favoring members of minorities in the hope that they will turn out to provide a different viewpoint.

In fact, at least in my observation, the people and departments most inclined to favor “diversity” in the conventional sense are among those least likely to want to hire professors whose viewpoints differ from the consensus. What they want are people of the desired gender or skin color who agree with them. My standard thought experiment to demonstrate this is to imagine that, at some late stage in the search process, it is discovered that a prospective hire regarded as a strong candidate is a supporter, an intelligent supporter, of South African apartheid. Does the probability of hiring him go up or down as a result? I can predict, with little data but some decades of experience of the academy, that in any elite university and almost any department it goes sharply down. Yet that is a viewpoint to which almost no faculty member or student has been, or expects to be, exposed. Someone who actually believes in intellectual diversity should thus regard the additional fact as a plus, not a minus.

When I offer this thought experiment, a common response is that there are no intelligent supporters of apartheid, hence the additional information shows something wrong with the prospective hire. I take that response as evidence in favor of my thesis. Almost nobody who makes it has had the opportunity to argue apartheid with a serious, sophisticated supporter--indeed, I suspect many of them have never met anyone who would admit to supporting it at all. Yet we know that millions of white South Africans did support it for quite a long period; it is a considerable stretch to claim that none of them could have been intelligent and thoughtful. And, in my thought experiment, the supporter of apartheid has already demonstrated sufficient ability to make him a strong candidate before his unfortunate political beliefs are discovered. The confident belief that no reasonable person could support a position that many otherwise reasonable people did support is strong evidence of the failure to be exposed to a sufficiently diverse range of views.

Academic hiring is not the only example of hostility to diversity by people who claim to favor it. Consider the issues of home schooling and education vouchers. It’s pretty clear, I think, to anyone involved in the controversy, that one of the main objections to both is that they foster diversity.

The objection is not, of course, put in those terms. It is rather that both make it possible for parents with the wrong views--in particular fundamentalist Christians--to indoctrinate their children with those views. The clear implication is that it is desirable to make sure that all children get exposed to, perhaps even indoctrinated with, the current consensus views--the ones that they will be taught in the public schools.

If one believes that fundamentalists are wrong and the current consensus correct, it’s reasonable enough to want all children exposed to the latter. But even given that belief, it is a position directly opposed to diversity--a desire to lessen diversity by stamping out, so far as possible, those particular dissenting views. And in at least some discussions, the hostility to diversity is explicit; the argument is precisely that it is desirable to have a society whose members share a common set of beliefs. That is, I think, a defensible position, but it is bizarre to have it expressed by people who purport to consider intellectual diversity a desirable objective

Thursday, June 07, 2007

Loaded Dice: How to bias research

In a recent Usenet thread, the question was raised of whether authoritarian personality types were more likely to be on the political right than on the political left. One contributor offered a link to a webbed book by Professor Robert Altmeyer which, the poster claimed, described scientific research that showed that the right was much more authoritarian than the left. I read the beginning of the book and concluded that it was indeed interesting--as an example of how to load the dice in order to get the results you want out of supposedly objective research.

The book starts off by defining "right wing authoritarian" (RWA) in a way which purports to be politically neutral; the author offers an implausible explanation of his entirely non-political reasons for labelling it "right wing." There follows the set of twenty questions (plus two that don't get scored) used to test subjects to see how RWA they are. On each question, the responder is supposed to express a view from "strongly agree" to "strongly disagree." The grading is simple--on some questions you count as more authoritarian the more strongly you agree, on the rest you count as more authoritarian the more strongly you disagree.

What is almost immediately obvious if you read the questions is that they aren't testing for RWA as the author defines it but for a combination of that and right/left political views. When the question is of the form "people who campaigned for unpopular causes X, Y and Z were good," X, Y and Z just happen to be causes more popular on the left than on the right. When the question is of the form "We should follow authority X," X just happens to be a source of authority, such as the church, more popular on the right than on the left. No questions about people who campaigned for unpopular right wing causes or about deferring to sources of authority popular on the left.

Perhaps the worst question of all was:

6. Atheists and others who have rebelled against the established religions are no doubt every bit as good and virtuous as those who attend church regularly.

Almost nobody taking the test--my guess is literally nobody--has the data needed to know whether atheists are less virtuous, more virtuous, or just as virtuous as churchgoers. The only reason I can see why someone would respond with "strongly agree" is that he is an authoritarian accepting the authority of a particular subgroup within his society--one that is skeptical of religion. But that is supposed to be the extreme non-authoritarian answer to the question.

Interested readers can find a more detailed critique by me on usenet; the thread, including responses, is here.

Monday, June 04, 2007

Stocks vs Bonds: A Puzzle and Half a Solution

On average, buying stocks gives you a better return than buying bonds. That has been true for a long time. The return from stocks is less predictable than that from bonds, but the difference in return is large enough to make risk aversion an inadequate explanation. That, at least, is my understanding of the conclusion of those who have studied the question.

This presents an obvious puzzle to an economist. If stocks provide a better return than bonds, investors should shift to stocks. Once prices have adjusted to the shift, the future return on stocks should be lower than before, on bonds higher, and the process should continue until the returns are roughly equal, allowing for the different risks of the two kinds of investment. Yet that does not seem to have happened.

Some time ago I came up with a solution. Unfortunately, there is a serious problem with it. The purpose of this post is to explain the solution in the hope that someone else can see how to patch the hole.

I start with a simple assumption: All investors have inside information. Someone who works in a company knows a little more than outsiders about the prospects for that company. Someone who has made a career in an industry has a feel for what is happening in the industry. An enthusiastic customer in some niche market knows better than most which products are good and which firms are likely to prosper. One of the functions of the stock market is to put together all of this dispersed information and come up with stock prices.

Suppose I have expert knowledge of the industry I work in and money to invest. Investing all of it in that industry is risky, especially if I work in that industry, since I don't want the risk on my investments to correlate with risks to my income. So I invest some of it in the industry, taking advantage of my special information to do so, and the rest elsewhere. On the margin I am getting the return of an uninformed investor, on the average something between that and the return of an expert investor. Since everyone else is doing the same thing, everyone is getting that result.

What about investing in bonds? Since I have already invested as much as I want in the area of my expertise, investments in bonds substitute for the uninformed part of my investment. So, in equilibrium, the return on bonds will (ignoring any risk premiums) equal the return on my marginal investment in stock and be lower than my average return on stock--explaining why, on average, stock gives a better return than bonds.

The problem with this is that it depends on my uninformed investment giving a worse result than investing at random, since random investments ought to pay me the average return on stocks.

Anyone with a good solution? It's worth noting that the problem applies to other and more conventional views of the stock market. In order for clever investors to do better than average, someone has to do worse.